What you would typically be looking at, is compliance witt the PDF/X standards [1] in various levels, which are basically ISO norms for PDFs.
Files for printing production need to have their fonts embedded, color profiles attached/at least tagged to images, transparency dealt with, lots of stuff that ensures that the PDF itself contains all the necessary information for a successful reproducting/printing on a printing machine of any kind.
As printing production systems have evolved, the rules became "less strict" as all (most) the systems can now handle transparency natively, for example. That for example was a big change with PDF/X4, before you had to convert (keyword is "transparency reduction") all transparencies and factor them into the underlying elements.
Most PDF generators out there are not able to follow the rules of ISO/the PDF/X specifications, so print shops might have a hard time handling that data, due to various missing pieces of information.
That's normally no deal for your office printer, but when you are looking at large(r) printing operations, it surely is.
The one is PDFlib [1] which can easily be accessed via Java and PHP. As a web guy, I'm using PHP obviously. There's some learning curve to it, and you have to take care of lots of stuff by yourself, but the results are pretty good afterwards.
The second are the products from callas, mainly pdfToolbox [2] and pdfChip [3], which are kind of the de facto standard for the printing industry, at least in my Western Europe bubble.
pdfChip is based around the WebKit rendering engine, so you can work with HTML + CSS and convert your document to a PDF file. The pdfChip internals will take care of PDF/X compliance, if you want to.
pdfToolbox and pdfChip both have a steep learning curve, too, but you'll probably find that with any software that is highly specialized.
Files for printing production need to have their fonts embedded, color profiles attached/at least tagged to images, transparency dealt with, lots of stuff that ensures that the PDF itself contains all the necessary information for a successful reproducting/printing on a printing machine of any kind.
As printing production systems have evolved, the rules became "less strict" as all (most) the systems can now handle transparency natively, for example. That for example was a big change with PDF/X4, before you had to convert (keyword is "transparency reduction") all transparencies and factor them into the underlying elements.
Most PDF generators out there are not able to follow the rules of ISO/the PDF/X specifications, so print shops might have a hard time handling that data, due to various missing pieces of information.
That's normally no deal for your office printer, but when you are looking at large(r) printing operations, it surely is.
[1] https://en.wikipedia.org/wiki/PDF/X